1. Field of the Invention
The present invention relates to valves and, more particularly, to a locking assembly for retaining and, if desired, locking a flow control member of a valve in an open or closed position.
2. Description of the Invention Background
Over the years, a variety of different types of valves for controlling the flow of fluids, vapors, slurries, etc. in pipelines or conduits have been developed. Examples of such flow control valves are butterfly valves, plug valves, globe valves, gate valves, diaphragm valves and ball valves. Each of these types of valves generally have different flow and pressure characteristics due to their different configurations.
On problem that is common to all valves, regardless of their particular construction, is the inability to lock such valves in a desired open or closed position to prevent their unauthorized actuation without the use of complicated and expensive locking mechanism. The reader will appreciate that such need to lock valves to prevent unauthorized actuation can arise in a variety of different settings and applications. For example, such ability is often desirable when valves are employed in pipelines that pass through remote areas to guard against vandalism and tampering. In manufacturing plants, it is often desirable to use valves that can be easily locked during process maintenance operations to prevent the valve from being inadvertently opened which could result in injuries to the maintenance personnel and equipment located downstream of the valve. In addition, valves are often used in locations wherein they are susceptible to the inadvertent application of forces which could cause them to be accidentally opened or closed. In such instances, it is desirable to employ a valve that has a means for retaining the flow control member thereof in a desired position even under the accidental application of a force to its actuation member.
A variety of different valve locking mechanisms have been developed which purport to address such problems. Examples of such mechanisms are disclosed in U.S. Pat. No. 3,228,415 to Geiss, U.S. Pat. No. 4,126,023 to Smith et al., U.S. Pat. Nos. 5,014,528, 5,183,073, and 5,579,804 to Roberts, U.S. Pat. No. 5,449,144 to Kowalics, and U.S. Pat. No. 5,709,112 to Kennedy. Each of those mechanisms, however, are relatively complicated to manufacture, assemble and install on the valve.
Therefore, there is a need for a locking apparatus that can be used in connection with a variety of different valve configurations that is easy to manufacture, install and operate.
There is a further need for a valve locking apparatus that can prevent the inadvertent actuation of a valve.
There is still another need for a valve locking apparatus that can be used in connection with a variety of different commercially available locks to prevent unauthorized actuation of a valve.
Yet another need exists for a locking apparatus that can be used in connection with a valve that can be actuated manually or automatically.
Another need exists for a valve locking apparatuses that can be easily retrofitted onto the valve stems of existing valves.
An additional need exists for a valve that has a means for preventing accidental actuation of the flow control member of the valve.
Still another need exists for a valve that has a locking apparatus that enables the flow control member of the valve to be locked in a desired position to prevent the unauthorized actuation thereof.